1. Field of the Invention
The present invention relates to an elevator door apparatus, particularly to an improvement in the fire protection construction thereof.
2. Description of the Related Art
FIG. 7 is a horizontal cross sectional view showing a conventional elevator door apparatus. In the drawing, an entrance 2 is provided in a landing wall 1. A jamb 3 is fixed to side edge portions and an upper edge portion of the entrance 2. End portions of the jamb 3 close to a hoist way 4 are bent in an L-shaped manner toward an inner portion of a door recess portion 5 to constitute a landing side engaging portion 3a. A pair of landing doors (fireproof doors) 6 for opening and closing the entrance 2 are provided at the inner side of the entrance 2. A fire protection member 7 is fixed to each opening side end portion of the landing doors 6. A door side engaging portion 7a having a U-shaped cross section is formed in each fire protection member 7 in such a manner as to oppose both surfaces of the landing side engaging portion 3a when the doors 6 are closed.
Next, FIG. 8 is a cross sectional view showing a deformed state of the landing doors 6 shown in FIG. 7 when there is a fire, and FIG. 9 is a cross sectional view taken along a line IX--IX in FIG. 8. When a fire occurs in the landing entrance side, the landing doors 6 are deformed by heat in the manner shown in FIGS. 8 and 9. At this time, the door side engaging portions 7a are brought into contact with the landing side engaging portions 3a, so that the deformation (warping) of the landing doors 6 is restricted. Accordingly, a large gap is prevented from developing between the landing entrance and the hoist way 4 due to the warping of the landing doors 6 and the fire is prevented from entering the hoist way 4. Here, the warp of the landing doors 6 is exaggerated in FIGS. 8 and 9 for easier understanding.
In the conventional elevator door apparatus having the above construction, since the door side engaging portions 7a project from the side end portions of the landing doors 6 in the direction that the doors open, in order to secure a clearance c with respect to the side wall of the hoist way 4 in the door open state (broken lines in FIG. 7), the width d.sub.o of the hoist way 4 must be increased at least twice the distance e (for example, 100 mm) that the door side engaging portion 7a projects compared to when fire protection members 7 are not used, so that the area of the building that the hoist way 4 occupies increases. Furthermore, it is necessary to determine if fire protection members 7 are to be provided at the building design stage, and this decreases design flexibility.